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Internet INTAREA Working Group Some IETF protocols make use of Ethernet frame formats and IEEE 802 parameters. This document discusses several aspects of such parameters, their use in IETF protocols, specifies IANA considerations for assignment of points under the IANA OUI (Organizationally Unique Identifier), and provides some values for use in documentation. This document obsoletes RFC 7042.

Introduction Some IETF protocols use Ethernet or other IEEE 802-related communication frame formats and parameters . These include MAC (Media Access Control) addresses and protocol identifiers. The IEEE provides a number of tutorials concerning these parameters . This document specifies IANA considerations for the assignment of code points under the IANA OUI (Organizationally Unique Identifier), including MAC addresses and protocol identifiers, and provides some values for use in documentation. As noted in and , the use of designated code values reserved for documentation and examples reduces the likelihood of conflicts and confusion arising from such code points conflicting with code points assigned for some deployed use. This document also discusses several other uses by the IETF of IEEE 802 code points, including IEEE 802 Connectivity Fault Management (CFM) code points and IEEE 802 Link Local Discovery Protocol (LLDP ) Vendor-Specific TLV Sub-Types . It also specifies CBOR tags for MAC addresses and OUI/CIDs. is incorporated herein except where there are contrary provisions in this document. In this document, "IESG Ratification" is used in some cases. "IESG Ratification" is specified in Section 5.1. It is NOT the same as "IESG Approval" in .

Notations Used in This Document This document uses hexadecimal notation. Each octet (that is, 8-bit byte) is represented by two hexadecimal digits giving the value of the octet as an unsigned integer. Successive octets are separated by a hyphen. This document consistently uses IETF ("network") bit ordering although the physical order of bit transmission within an octet on an IEEE link is from the lowest order bit to the highest order bit (i.e., the reverse of the IETF's ordering). In this document:

"AFN"

Address Family Number .

"CBOR"

Concise Binary Object Representation .

"CFM"

Connectivity Fault Management .

"CID"

Company Identifier.

"DSAP"

Destination Service Access Point. See Section 3.

"EUI"

Extended Unique Identifier.

"IAB"

Individual Address Block, not Internet Architecture Board. Now called MA-S.

"IEEE"

Institute for Electrical and Electronics Engineers .

"IEEE-SA"

IEEE Standards Association .

"LSAP"

Link-Layer Service Access Point. See Section 3.

"MA-L"

MAC Address Block Large, commonly referred to as an OUI.

"MA-M"

MAC Address Block Medium.

"MA-S"

MAC Address Block Small.

"MAC"

Media Access Control, not Message Authentication Code.

"MAC-48"

A 48-bit MAC address. This term is obsolete. If globally unique, use EUI-48.

"OUI"

Organizationally Unique Identifier. An OUI is now officially called an "MA-L" by the IEEE.

"RRTYPE"

A DNS Resource Record type .

"SLAP"

IEEE 802 Structured Local Address Plan .

"SSAP"

Source Service Access Point. See Section 3.

"tag"

"Tag" is used in two contexts in this document. For "Ethernet tag", see Section 3. For "CBOR tag", see Section 2.4.

"TLV"

Type, Length, Value.

"**"

The double asterisk symbol indicates exponentiation. For example, 2**24 is two to the twenty-fourth power.

Changes from RFC 7042 This document obsoletes and makes the changes listed below. However, the completed application template based upon which an IANA OUI-based protocol number value was assigned for document use remains that in Appendix C of RFC 7042.

• Add information on MA-M (28-bit) and MA-S (36-bit) EUI prefixes that the IEEE Registration Authority assigns.
• Add information on the restructuring of the "local" MAC address space into four quadrants under the Structured Local Address Plan (SLAP ).
• Include the IESG Statement on Ethertypes (See Appendix B.1) and more detailed IETF procedures for applying to the IEEE Registration Authority for an Ethertype for use in an IETF protocol (see Section 5.5).
• Mention that IEEE 802 CFM Codepoints that have been allocated to the IETF (see Section 1.5).
• Mention the vendor specific LLDP data element that has been assigned under the IANA OUI and the registry set up for future such assignments (see Section 4.1).
• Clarify minor details in Section 5.1 on Expert Review and IESG Ratification.
• Specify CBOR tags for MAC addresses and OUI/CIDs (see Section 2.4).
• Add a version field requirement for the allocation of protocol numbers under the IANA OUI (see Section 3.1).

The IEEE Registration Authority Originally the responsibility of Xerox Corporation, the registration authority for Ethernet parameters is now the IEEE Registration Authority, available on the web at . The IEEE Registration Authority operates under the direction of the IEEE Standards Association (IEEE-SA) Board of Governors, normally via the IEEE Registration Authority Committee (RAC). The IEEE RAC is a committee of the Board of Governors. Anyone may apply to that Authority for parameter assignments. The IEEE Registration Authority may impose fees or other requirements but commonly waives fees for applications from standards development organizations. Lists of assignments and their holders are downloadable from the IEEE Registration Authority site.

The IANA Organizationally Unique Identifier The Organizationally Unique Identifier (OUI) 00-00-5E has been assigned to IANA by the IEEE Registration Authority. There is no OUI value reserved at this time for documentation, but there are documentation code points under the IANA OUI specified below.

CFM Code Points The IEEE has allocated two blocks of 802 Connectivity Fault Management (CFM) code points to the IETF, one for CFM OpCodes and one for CFM TLV Types. For further information see . The IANA "Connectivity Fault Management (CFM) OAM IETF Parameters" Registry has subregistries for these code points. This document does not further discuss these blocks of code points.

Ethernet Identifier Parameters Section 2.1 discusses 48-bit MAC identifiers, their relationship to OUIs and other prefixes, and assignment under the IANA OUI. Section 2.2 extends this to 64-bit identifiers. Section 2.3 discusses other IETF MAC identifier use not under the IANA OUI. Section 2.4 specifies CBOR tags for MAC addresses and OUI/CIDs. Historical Note: indicates that the IEEE Registration Authority Committee was at one time exploring the feasibility of defining 128-bit identifiers. [RAC_OUI] is an expired draft that also provides additional historic information on registries.

48-Bit MAC Identifiers, OUIs, and Other Prefixes 48-bit MAC "addresses" are the most commonly used Ethernet interface identifiers. Those that are globally unique are also called EUI-48 identifiers (Extended Unique Identifier 48). An EUI-48 is structured into an initial prefix assigned by the IEEE Registration Authority and additional bits assigned by the prefix owner. Currently there are three lengths of prefixes assigned as shown in the table below; however, some prefix bits have special meaning as shown in .

Prefix Length in bits	Name>	Owner Supplied Bits for EUI-48
24	MA-L (OUI)	24
28	MA-M	20
36	MA-S	12

The bottom four bits, as shown in , of the first octet of the 3-octet 48-bit MAC have special meaning and are referred to below as the M, X, Y, and Z bits.

48-bit MAC Address Structure

Except for certain combinations of the Z, Y, X and M bits as discussed in Section 2.1.1, a MAC address begins with 3 octets or a larger initial prefix indicating the assignee of the block of MAC addresses. This prefix is followed by a sequence of additional octets so as to add up to the total MAC address length. For example, the IEEE assigns MA-S (MAC Address Block Small), where the first 4 1/2 octets (36 bits) are assigned, giving the holder of the MA-S 1 1/2 octets (12 bits) they can control in constructing 48-bit MAC addresses; other prefix lengths are also available [RAC_OUI]. An AFN, a DNS RRTYPE, and a CBOR tag have been assigned for 48-bit MAC addresses as discussed in Sections 2.4, 5.3 and 5.9. The IEEE describes its assignment procedures and policies for IEEE 802-related identifiers in . An IEEE tutorial on EUIs, OUIs, and CIDs is available at .

Special First Octet Bits Four bits within the initial octet of an IEEE MAC interface identifier, such as an EUI-48, have special significance as follows:

M bit

---- This bit always indicates a group address and is frequently referred to as the group bit. If it is zero, the MAC address is unicast. If it is a one, the address is groupcast (multicast or broadcast). This meaning is independent of the values of the X, Y, and Z bits.

X bit

---- This bit was previously called the "local" bit. If it is zero, the MAC address is a global address under the control of the owner of the IEEE assigned prefix. Previously, if it was a one, the MAC address was considered "local" and under the assignment and control of the local network operator (but see Section 2.3). If it is a one and if the IEEE 802 Structured Local Address Plan (SLAP) is in effect, the nature of the MAC address is optionally determined by the Y and Z bits as described below.

Y+Z bits

- These two bits have no special meaning if the X bit is zero. If the X bit is one then, if the IEEE 802 Structured Local Address Plan (SLAP) is in effect, these two bits divide the formerly uniform "local" MAC address space into four quadrants, as follows and further described below:

Y bit	Z bit	Quadrant
0	0	Administratively Assigned
0	1	Extended Local
1	0	Reserved
1	1	Standard Assigned

While a local network administrator can assign any addresses with the X bit a one, the optional SLAP characterizes the four quadrants of the "local" address space using the Y and Z bits as follows:

Administratively Assigned -

MAC addresses in this quadrant are called Administratively Assigned Identifiers. This is intended for arbitrary local assignment, such as random assignment; however, see Section 2.3.1.

Extended Local -

MAC addresses in this quadrant are called Extended Local Identifiers. These addresses are not actually "local" under SLAP. They are available to the organization that has been assigned the CID (see Section 2.1.2) specifying the other 20 bits of the 24-bit prefix with X, Y, and Z bits having the values 1, 0, and 1 respectively.

Reserved -

MAC addresses in this quadrant are reserved for future use under the SLAP. Until such future use, they could be locally assigned as Administratively Assigned Identifiers are assigned but there is a danger that future SLAP use would conflict with such local assignments.

Standard Assigned -

MAC addresses in this quadrant are called Standard Assigned Identifiers. It is intended that such addresses be assigned and possibly revoked through a local protocol. Both IEEE and the IETF have adopted such protocols.

OUIs and CIDs MA-L (OUI), MA-M, and MA-S MAC prefixes are assigned with the Local bit zero and the Group bit unspecified. Multicast identifiers may be constructed by turning on the Group bit and unicast identifiers may be constructed by leaving the Group bit zero. The Local bit is zero for globally unique EUI-48 identifiers assigned by the owner of a MAC-L (OUI) or owner of a longer prefix. If the Local bit is a one, the identifier has historically been a local identifier under the control of the local network administrator; however, there are now recommendations on optional management of the local address space as discussed in Section 2.1.1. If the Local bit is a one, the holder of an OUI has no special authority over MAC identifiers whose first 3 octets correspond to their OUI or the beginning of their longer prefix. A CID is a 24-bit Company Identifier. It is assigned for organizations that need such an identifier, that can be used in place of an OUI, but do not need to assign subsidiary MAC addresses. A CID can be recognized by its X and Z bits having the value 1 and its Y bit having the value 0 (see ). An AFN and a CBOR tag have been assigned for OUI/CIDs as discussed in Sections 2.4, 5.3 and 5.9.

EUI-48 Assignments under the IANA OUI The OUI 00&nbhy;00&nbhy;5E has been assigned to IANA as stated in Section 1.4 above. This includes 2**24 EUI&nbhy;48 multicast identifiers from 01&nbhy;00&nbhy;5E&nbhy;00&nbhy;00&nbhy;00 to 01&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FF&nbhy;FF and 2**24 EUI&nbhy;48 unicast identifiers from 00&nbhy;00&nbhy;5E&nbhy;00&nbhy;00&nbhy;00 to 00&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FF&nbhy;FF. Of these EUI&nbhy;48 identifiers, the sub-blocks reserved or thus far assigned are as follows: Unicast, all blocks of 2**8 addresses thus far:

00&nbhy;00&nbhy;5E&nbhy;00&nbhy;00&nbhy;00 through 00&nbhy;00&nbhy;5E&nbhy;00&nbhy;00&nbhy;FF:

reserved and require IESG Ratification for assignment (see Section 5.1).

00&nbhy;00&nbhy;5E&nbhy;00&nbhy;01&nbhy;00 through 00&nbhy;00&nbhy;5E&nbhy;00&nbhy;01&nbhy;FF:

assigned for the Virtual Router Redundancy Protocol (VRRP) .

00&nbhy;00&nbhy;5E&nbhy;00&nbhy;02&nbhy;00 through 00&nbhy;00&nbhy;5E&nbhy;00&nbhy;02&nbhy;FF:

assigned for the IPv6 Virtual Router Redundancy Protocol (IPv6 VRRP) .

00&nbhy;00&nbhy;5E&nbhy;00&nbhy;52&nbhy;00 through 00&nbhy;00&nbhy;5E&nbhy;00&nbhy;52&nbhy;FF:

used for very small assignments. Currently, 4 out of these 256 values have been assigned.

00&nbhy;00&nbhy;5E&nbhy;00&nbhy;53&nbhy;00 through 00&nbhy;00&nbhy;5E&nbhy;00&nbhy;53&nbhy;FF:

assigned for use in documentation.

00&nbhy;00&nbhy;5E&nbhy;90&nbhy;01&nbhy;00 through 00&nbhy;00&nbhy;5E&nbhy;90&nbhy;01&nbhy;FF:

used for very small assignments that need parallel unicast and multicast MAC addresses. Currently 1 out of these 256 values has been assigned.

Multicast:

01&nbhy;00&nbhy;5E&nbhy;00&nbhy;00&nbhy;00 through 01&nbhy;00&nbhy;5E&nbhy;7F&nbhy;FF&nbhy;FF:

2**23 addresses assigned for IPv4 multicast .

01&nbhy;00&nbhy;5E&nbhy;80&nbhy;00&nbhy;00 through 01&nbhy;00&nbhy;5E&nbhy;8F&nbhy;FF&nbhy;FF:

2**20 addresses assigned for MPLS multicast .

01&nbhy;00&nbhy;5E&nbhy;90&nbhy;00&nbhy;00 through 01&nbhy;00&nbhy;5E&nbhy;90&nbhy;00&nbhy;FF:

2**8 addresses being used for very small assignments. Currently, 4 out of these 256 values have been assigned.

01&nbhy;00&nbhy;5E&nbhy;90&nbhy;01&nbhy;00 through 01&nbhy;00&nbhy;5E&nbhy;90&nbhy;01&nbhy;FF:

used for very small assignments that need parallel unicast and multicast MAC addresses. Currently 1 out of these 256 values has been assigned.

01&nbhy;00&nbhy;5E&nbhy;90&nbhy;10&nbhy;00 through 01&nbhy;00&nbhy;5E&nbhy;90&nbhy;10&nbhy;FF:

2**8 addresses for use in documentation.

For more detailed and up-to-date information, see the "Ethernet Numbers" registry at http://www.iana.org.

EUI-48 Documentation Values The following values have been assigned for use in documentation:

• 00&nbhy;00&nbhy;5E&nbhy;00&nbhy;53&nbhy;00 through 00&nbhy;00&nbhy;5E&nbhy;00&nbhy;53&nbhy;FF for unicast and
• 01&nbhy;00&nbhy;5E&nbhy;90&nbhy;10&nbhy;00 through 01&nbhy;00&nbhy;5E&nbhy;90&nbhy;10&nbhy;FF for multicast.

EUI-48 IANA Assignment Considerations EUI-48 assignments under the current or a future IANA OUI (see Section 5.6) must meet the following requirements:

• must be for standards purposes (either for an IETF Standard or other standard related to IETF work),
• must be for a power-of-two size block of identifiers starting at a boundary that is an equal or greater power of two, including the assignment of one (2**0) identifier,
• must not be used to evade the requirement for network interface vendors to obtain their own block of identifiers from the IEEE, and
• must be documented in an Internet-Draft or RFC.

In addition, approval must be obtained as follows (see the procedure in Section 5.1):

• Small to medium assignments of a block of 1, 2, 4, ..., 32768, 65536 (2**0, 2**1, 2**2, ..., 2**15, 2**16) EUI-48 identifiers require Expert Review (see Section 5.1).
• Large assignments of 131072 (2**17) or more EUI-48 identifiers require IESG Ratification (see Section 5.1).

64-Bit MAC Identifiers IEEE also defines a system of 64-bit MAC identifiers including EUI&nbhy;64s. EUI&nbhy;64 identifiers are currently used as follows:

• In a modified form to construct some IPv6 interface identifiers as described in Section 2.2.1
• In IEEE Std 1394 (also known as FireWire and i.Link)
• In IEEE Std 802.15.4 (also known as ZigBee)
• In

Adding a 5-octet (40-bit) extension to a 3-octet (24-bit) OUI (MA-L), or a shorter extension to longer assigned prefixes [RAC_OUI] so as to total 64 bits, produces an EUI-64 identifier under that OUI or longer prefix. As with EUI-48 identifiers, the first octet has the same special low order bits. An AFN, a DNS RRTYPE, and CBOR tag have been assigned for 64-bit MAC addresses as discussed in Sections 2.4, 5.3, and 5.9. The discussion below is almost entirely in terms of the "Modified" form of EUI-64 identifiers; however, anyone assigned such an identifier can also use the unmodified form as a MAC identifier on any link that uses such 64-bit identifiers for interfaces.

IPv6 Use of Modified EUI-64 Identifiers MAC-64 identifiers are used to form the lower 64 bits of some IPv6 addresses (Section 2.5.1 and Appendix A of and Appendix A of ). When so used, the MAC-64 is modified by inverting the X (Local/Global) bit to form an IETF "Modified EUI-64 identifier". Below is an illustration of a Modified EUI-64 unicast identifier under the IANA OUI, where aa-bb-cc-dd-ee is the extension. 02-00-5E-aa-bb-cc-dd-ee The first octet is shown as 02 rather than 00 because, in Modified EUI-64 identifiers, the sense of the X bit is inverted compared with EUI-48 identifiers. It is the globally unique values (universal scope) that have the 02 bit on in the first octet, while those with this bit off are typically locally assigned and out of scope for global assignment. The X (Local/Global) bit was inverted to make it easier for network operators to type in local-scope identifiers. Thus, such Modified EUI-64 identifiers as 1, 2, etc. (ignoring leading zeros) are local. Without the modification, they would have to be 02-00-00-00-00-00-00-01, 02-00-00-00-00-00-00-02, etc. to be local. As with 48-bit MAC identifiers, the 01 bit on in the first octet indicates a group identifier (multicast or broadcast). When the first two octets of the extension of a Modified EUI-64 identifier are FF-FE, the remainder of the extension is a 24-bit value as assigned by the OUI owner for an EUI-48. For example: 02-00-5E-FF-FE-yy-yy-yy or 03-00-5E-FF-FE-yy-yy-yy where yy-yy-yy is the portion (of an EUI-48 global unicast or multicast identifier) that is assigned by the OUI owner (IANA in this case). Thus, any holder of one or more EUI-48 identifiers under the IANA OUI also has an equal number of Modified EUI-64 identifiers that can be formed by inserting FF-FE in the middle of their EUI-48 identifiers and inverting the Local/Global bit. In addition, certain Modified EUI-64 identifiers under the IANA OUI are reserved for holders of IPv4 addresses as follows: 02-00-5E-FE-xx-xx-xx-xx where xx-xx-xx-xx is a 32-bit IPv4 address. The owner of an IPv4 address has both a unicast- and multicast-derived EUI-64 address. Modified EUI-64 identifiers from 02-00-5E-FE-F0-00-00-00 to 02-00-5E-FE-FF-FF-FF-FF are effectively reserved pending the specification of IPv4 "Class E" addresses . However, for Modified EUI-64 identifiers based on an IPv4 address, the Local/Global bit should be set to correspond to whether the IPv4 address is local or global. (Keep in mind that the sense of the Modified EUI-64 identifier Local/Global bit is reversed from that in (unmodified) MAC-64 identifiers.)

EUI-64 IANA Assignment Considerations The following table shows which Modified EUI-64 identifiers under the IANA OUI are reserved, assigned, or available as indicated. As noted above, the corresponding MAC addresses can be determined by complementing the 02 bit in the first octet. In all cases, the corresponding multicast 64-bit MAC addresses formed by complementing the 01 bit in the first octet have the same status as the modified 64-bit unicast address blocks listed below.

02&nbhy;00&nbhy;5E&nbhy;00&nbhy;00&nbhy;00&nbhy;00&nbhy;00 to 02&nbhy;00&nbhy;5E&nbhy;0F&nbhy;FF&nbhy;FF&nbhy;FF&nbhy;FF

reserved

02&nbhy;00&nbhy;5E&nbhy;10&nbhy;00&nbhy;00&nbhy;00&nbhy;00 to 02&nbhy;00&nbhy;5E&nbhy;10&nbhy;00&nbhy;00&nbhy;00&nbhy;FF

assigned for documentation use

02&nbhy;00&nbhy;5E&nbhy;10&nbhy;00&nbhy;00&nbhy;01&nbhy;00 to 02&nbhy;00&nbhy;5E&nbhy;EF&nbhy;FF&nbhy;FF&nbhy;FF&nbhy;FF

available for assignment

02&nbhy;00&nbhy;5E&nbhy;F0&nbhy;00&nbhy;00&nbhy;00&nbhy;00 to 02&nbhy;00&nbhy;5E&nbhy;FD&nbhy;FF&nbhy;FF&nbhy;FF&nbhy;FF

reserved

02&nbhy;00&nbhy;5E&nbhy;FE&nbhy;00&nbhy;00&nbhy;00&nbhy;00 to 02&nbhy;00&nbhy;5E&nbhy;FE&nbhy;FF&nbhy;FF&nbhy;FF&nbhy;FF

assigned to IPv4 address holders as described above

02&nbhy;00&nbhy;5E&nbhy;FF&nbhy;00&nbhy;00&nbhy;00&nbhy;00 to 02&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FD&nbhy;FF&nbhy;FF&nbhy;FF

reserved

02&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FE&nbhy;00&nbhy;00&nbhy;00 to 02&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FE&nbhy;FF&nbhy;FF&nbhy;FF

assigned for holders of EUI&nbhy;48 identifiers under the IANA OUI as described above

02&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FF&nbhy;00&nbhy;00&nbhy;00 to 02&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FF&nbhy;FF&nbhy;FF&nbhy;FF

reserved

The reserved identifiers above require IESG Ratification (see Section 5.1) for assignment. IANA EUI-64 identifier assignments under the IANA OUI must meet the following requirements:

• must be for standards purposes (either for an IETF Standard or other standard related to IETF work),
• must be for a power-of-two size block of identifiers starting at a boundary that is an equal or greater power of two, including the assignment of one (2**0) identifier,
• must not be used to evade the requirement for network interface vendors to obtain their own block of identifiers from the IEEE, and
• must be documented in an Internet-Draft or RFC.

In addition, approval must be obtained as follows (see the procedure in Section 5.1):

• Small to medium assignments of a block of 1, 2, 4, ..., 134217728, 268435456 (2**0, 2**1, 2**2, ..., 2**27, 2**28) EUI-64 identifiers require Expert Review (see Section 5.1).
• Large assignments of 536870912 (2**29) or more EUI-64 identifiers require IESG Ratification (see Section 5.1).

EUI-64 Documentation Values The following blocks of unmodified 64-bit MAC addresses are for documentation use. The IPv4-derived addresses are based on the IPv4 documentation addresses , and the MAC-derived addresses are based on the EUI-48 documentation addresses above. Unicast values for Documentation Use: 00&nbhy;00&nbhy;5E&nbhy;EF&nbhy;10&nbhy;00&nbhy;00&nbhy;00 to 00&nbhy;00&nbhy;5E&nbhy;EF&nbhy;10&nbhy;00&nbhy;00&nbhy;FF general 00&nbhy;00&nbhy;5E&nbhy;FE&nbhy;C0&nbhy;00&nbhy;02&nbhy;00 to 00&nbhy;00&nbhy;5E&nbhy;FE&nbhy;C0&nbhy;00&nbhy;02&nbhy;FF and 00&nbhy;00&nbhy;5E&nbhy;FE&nbhy;C6&nbhy;33&nbhy;64&nbhy;00 to 00&nbhy;00&nbhy;5E&nbhy;FE&nbhy;C6&nbhy;33&nbhy;64&nbhy;FF and 00&nbhy;00&nbhy;5E&nbhy;FE&nbhy;CB&nbhy;00&nbhy;71&nbhy;00 to 00&nbhy;00&nbhy;5E&nbhy;FE&nbhy;CB&nbhy;00&nbhy;71&nbhy;FF IPv4 derived 00&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FE&nbhy;00&nbhy;53&nbhy;00 to 00&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FE&nbhy;00&nbhy;53&nbhy;FF EUI-48 derived 00&nbhy;00&nbhy;5E&nbhy;FE&nbhy;EA&nbhy;C0&nbhy;00&nbhy;02 and 00&nbhy;00&nbhy;5E&nbhy;FE&nbhy;EA&nbhy;C6&nbhy;33&nbhy;64 and 00&nbhy;00&nbhy;5E&nbhy;FE&nbhy;EA&nbhy;CB&nbhy;00&nbhy;71 IPv4 multicast derived from IPv4 unicast Multicast values for Documentation Use: 01&nbhy;00&nbhy;5E&nbhy;EF&nbhy;10&nbhy;00&nbhy;00&nbhy;00 to 01&nbhy;00&nbhy;5E&nbhy;EF&nbhy;10&nbhy;00&nbhy;00&nbhy;FF general 01&nbhy;00&nbhy;5E&nbhy;FE&nbhy;C0&nbhy;00&nbhy;02&nbhy;00 to 01&nbhy;00&nbhy;5E&nbhy;FE&nbhy;C0&nbhy;00&nbhy;02&nbhy;FF and 01&nbhy;00&nbhy;5E&nbhy;FE&nbhy;C6&nbhy;33&nbhy;64&nbhy;00 to 01&nbhy;00&nbhy;5E&nbhy;FE&nbhy;C6&nbhy;33&nbhy;64&nbhy;FF and 01&nbhy;00&nbhy;5E&nbhy;FE&nbhy;CB&nbhy;00&nbhy;71&nbhy;00 to 01&nbhy;00&nbhy;5E&nbhy;FE&nbhy;CB&nbhy;00&nbhy;71&nbhy;FF IPv4 derived 01&nbhy;00&nbhy;5E&nbhy;FE&nbhy;EA&nbhy;C0&nbhy;00&nbhy;02 and 01&nbhy;00&nbhy;5E&nbhy;FE&nbhy;EA&nbhy;C6&nbhy;33&nbhy;64 and 01&nbhy;00&nbhy;5E&nbhy;FE&nbhy;EA&nbhy;CB&nbhy;00&nbhy;71 IPv4 multicast derived from IPv4 unicast 01&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FE&nbhy;90&nbhy;10&nbhy;00 to 01&nbhy;00&nbhy;5E&nbhy;FF&nbhy;FE&nbhy;90&nbhy;10&nbhy;FF EUI-48 derived

Other 48-bit MAC Identifiers Used by the IETF There are two other blocks of 48-bit MAC identifiers that are used by the IETF as described below.

Identifiers with a '33-33' Prefix All 48-bit multicast MAC identifiers prefixed "33-33" (that is, the 2**32 multicast MAC identifiers in the range from 33-33-00-00-00-00 to 33-33-FF-FF-FF-FF) are used as specified in for IPv6 multicast. In all of these identifiers, the Group bit (the bottom bit of the first octet) is on, as is required to work properly with existing hardware as a multicast identifier. They also have the Local bit on but any Ethernet using standard IPv6 multicast should note that these addresses will be used for that purpose. These multicast MAC addresses fall into the Administratively Assigned SLAP quadrant (see Section 2.1.1). Historical notes: It was the custom during IPv6 design to use "3" for unknown or example values and 3333 Coyote Hill Road, Palo Alto, California, is the address of PARC (Palo Alto Research Center, formerly "Xerox PARC"). Ethernet was originally specified by the Digital Equipment Corporation, Intel Corporation, and Xerox Corporation. The pre-IEEE Ethernet protocol has sometimes been known as "DIX" Ethernet from the first letters of the names of these companies.

The 'CF Series' The Informational declared the 3-octet values from CF-00-00 through CF-FF-FF to be "OUIs" available for assignment by IANA to software vendors for use in PPP or for other uses where vendors do not otherwise need an IEEE-assigned OUI. When used as 48-bit MAC prefixes, these values have all of the Z, Y, X (Local), and M (Group) special bits at the bottom of the first octet equal to one, while all IEEE-assigned OUIs thus far have the X and M bits zero and all CIDs have bits Y and M zero; thus there can be no conflict between CF Series "OUI"s and IEEE assigned OUI/CIDs. Multicast MAC addresses constructed with a "CF" series OUI would fall into the standard assigned SLAP quadrant (see Section 2.1.1). The Group bit is meaningless in PPP. To quote : "The 'CF0000' series was arbitrarily chosen to match the PPP NLPID 'CF', as a matter of mnemonic convenience." (For further information on NLPIDs, see .) CF-00-00 is reserved, and IANA lists multicast identifier CF-00-00-00-00-00 is used for Ethernet loopback tests. In over a decade of availability, only a handful of values in the CF Series have been assigned. (See "Ethernet Numbers" and "PPP Numbers" ).

Changes to RFC 2153 The IANA Considerations in were updated as follows by the approval of RFC 5342 and remain so updated (no technical changes have been made):

• Use of these 'CF Series' identifiers based on IANA assignment was deprecated.
• IANA was instructed not to assign any further values in the 'CF Series'.

CBOR Tags The Concise Binary Object Representation (CBOR ) is a data format whose design goals include the possibility of very small code size, fairly small message size, and extensibility. In CBOR, a data item can be enclosed by a CBOR tag to give it some additional semantics identified by that tag. IANA has assigned TBD1 as the CBOR tag to indicate a MAC address. The enclosed data item is a byte string. The length of the byte string indicates whether a 48-bit (6 byte) or 64-bit (8 byte) MAC address is encoded. Should some other multiple of 8 bits length MAC addresses be used in the future, such as a 128-bit (16 byte) MAC address, the TBD1 tag will be used. IANA has assigned TDB2 as the CBOR tag to indicate an OUI, CID, or "CF" series organizational identifier. The enclosed data item is a byte string of length 3 to hold the 24-bit OUI or CID (see Section 2.1.2).

Ethernet Protocol Parameters Ethernet protocol parameters provide a means of indicating the contents of a frame -- for example, that its contents are IPv4 or IPv6. There are two types of protocol identifier parameters that can occur in Ethernet frames after the initial MAC address destination and source identifiers:

Ethertypes:

These are 16-bit identifiers appearing as the initial two octets after the MAC destination and source (or after a tag), which, when considered as an unsigned integer, are equal to or larger than 0x0600. (See .) specifies two Ethertypes for local, experimental use: 0x88B5 and 0x88B6.

LSAPs:

These are 8-bit protocol identifiers that occur in pairs immediately after an initial 16-bit (two-octet) remaining frame length, which is in turn after the MAC destination and source (or after a tag). Such a length must, when considered as an unsigned integer, be less than 0x5DC, or it could be mistaken as an Ethertype. LSAPs occur in pairs where one is intended to indicate the source protocol handler (SSAP) and one the destination protocol handler (DSAP); however, use cases where the two are different have been relatively rare. (See where the CTL field value of 3 indicates datagram service.)

Ethertype Frame Protocol Labeling

LSAP Frame Protocol Labeling

The concept has been extended to labeling by Ethernet "tags". An Ethernet tag in this sense is a prefix whose type is identified by an Ethertype that is then followed by either another tag, an Ethertype, or an LSAP (Link-Layer Service Access Point) protocol indicator for the "main" body of the frame, as described below. Traditionally, in the world, tags are a fixed length and do not include any encoding of their own length. Any device that is processing a frame cannot, in general, safely process anything in the frame past an Ethertype it does not understand. An example is the C-Tag (formerly the Q-Tag) . It provides customer VLAN and priority information for a frame. Neither Ethertypes nor LSAPs are assigned by IANA; they are assigned by the IEEE Registration Authority (see Section 1.3 above and Appendix B). However, both LSAPs and Ethertypes have extension mechanisms so that they can be used with five-octet Ethernet protocol identifiers under an OUI, including those assigned by IANA under the IANA OUI. When using the IEEE 802 Logical Link Control (LLC) format (Subnetwork Access Protocol (SNAP)) for a frame, an OUI-based protocol identifier can be expressed as follows: xx-xx-AA-AA-03-yy-yy-yy-zz-zz where xx-xx is the frame length and, as above, must be small enough not to be confused with an Ethertype; "AA" is the LSAP that indicates this use and is sometimes referred to as the SNAP Service Access Point (SNAP SAP); "03" is the LLC control octet indicating datagram service; yy-yy-yy is an OUI; and zz-zz is a protocol number, under that OUI, assigned by the OUI owner. The five-octet length for such OUI-based protocol identifiers was chosen so that, with the LLC control octet ("03"), the result is 16-bit aligned. When using an Ethertype to indicate the main type for a frame body, the special "OUI Extended Ethertype" 88-B7 is available. Using this Ethertype, a frame body can begin with 88-B7-yy-yy-yy-zz-zz where yy-yy-yy and zz-zz have the same meaning as in the SNAP format described above. It is also possible, within the SNAP format, to use an arbitrary Ethertype. Putting the Ethertype as the zz-zz field after an all- zeros OUI (00-00-00) does this. It looks like xx-xx-AA-AA-03-00-00-00-zz-zz where zz-zz is the Ethertype. (Note that, at this point, the 802 protocol syntax facilities are sufficiently powerful that they could be chained indefinitely. Whether support for such chaining is generally required is not clear, but requires support for xx-xx-AA-AA-03-00-00-00-88-B7-yy-yy-yy-zz-zz although this could be more efficiently expressed by simply pinching out the "00-00-00-88-B7" in the middle.) As well as labeling frame contents, 802 protocol types appear within NBMA (Non-Broadcast Multi-Access) Next Hop Resolution Protocol messages. Such messages have provisions for both two-octet Ethertypes and OUI-based protocol types. 16-bit Ethertypes also occur in the Generic Router Encapsulation (GRE ) header.

Ethernet Protocol Assignment under the IANA OUI Two-octet protocol numbers under the IANA OUI are available, as in 88-B7-00-00-0E-qq-qq or xx-xx-AA-AA-03-00-00-5E-qq-qq where qq-qq is the protocol number. A number of such assignments have been made out of the 2**16 protocol numbers available from 00-00-5E-00-00 to 00-00-5E-FF-FF (see ). The extreme values of this range, 00-00-5E-00-00 and 00-00-5E-FF-FF, are reserved and require IESG Ratification for assignment (see Section 5.1). New assignments of protocol numbers (qq-qq) under the IANA OUI must meet the following requirements:

• the assignment must be for standards use (either for an IETF Standard or other standard related to IETF work),
• the protocol must include a version field at a fixed offset or an equivalent marking such that later version can be indicated in a way recognizable by earlier versions,
• it must be documented in an Internet-Draft or RFC, and
• such protocol numbers are not to be assigned for any protocol that has an Ethertype. (Either that Ethertype can be used directly or, in the LSAPs case, using the SNAP SAP and putting an all-zeros "OUI" before the Ethertype as described above.)

In addition, the Expert Review (or IESG Ratification for the two reserved values) must be obtained using the procedure specified in Section 5.1.

Documentation Protocol Number 0x0042 is a protocol number under the IANA OUI (that is, 00&nbhy;00&nbhy;5E&nbhy;00&nbhy;42) to be used as an example for documentation purposes.

Other OUI-Based Parameters Some IEEE 802 and other protocols provide for parameters based on an OUI beyond those discussed above. Such parameters commonly consist of an OUI plus one octet of additional value. They are usually called "vendor specific" parameters, although "organization specific" might be more accurate. They would look like yy-yy-yy-zz where yy-yy-yy is the OUI and zz is the additional specifier. An example is the Cipher Suite Selector in . Values may be assigned under the IANA OUI for such other OUI-based parameter usage by Expert Review except that, for each use, the additional specifier values consisting of all zero bits and all one bits (0x00 (00-00-5E-00) and 0xFF (00-00-5E-FF) for a one-octet specifier) are reserved and require IESG Ratification (see Section 5.1) for assignment; also, the additional specifier value 0x42 (00-00-5E-42) is assigned for use as an example in documentation. Assignments of such other IANA OUI-based parameters must be for standards use (either for an IETF Standard or other standard related to IETF work) and be documented in an Internet-Draft or RFC. The first time a value is assigned for a particular parameter of this type, an IANA registry will be created to contain that assignment and any subsequent assignments of values for that parameter under the IANA OUI. The Expert may specify the name of the registry. If different policies from those above are required for such a parameter, a BCP or Standards Track RFC should be adopted to update this BCP and specify the new policy and parameter.

LLDP IETF Vendor-Specific TLV Type An example of such an "other IANA OUI based parameter" is specified in . This provides for a "vendor based" TLV type for announcing a Manufacturer Usage Description (MUD) Uniform Resource Locator (URL) in the IEEE Link Local Discovery Protocol (LLDP ). Additional IETF use of code points in this space have been proposed . (See also Section 5.8.)

IANA Considerations This document concerns IANA considerations for the assignment of Ethernet parameters in connection with the IANA OUI and related matters. Note: The "IETF OUI Ethernet Numbers" IANA web page is for registries of numbers assigned under the IANA OUI while the "IEEE 802 Numbers" IANA web page has Informational lists of numbers assigned by the IEEE Registration Authority. This document does not create any new IANA registries. The MAC address values assigned for documentation and the protocol number for documentation were both assigned by . No existing assignment is changed by this document.

Expert Review and IESG Ratification This section specifies the procedure for Expert Review and IESG Ratification of MAC, protocol, and other IANA OUI-based identifiers. The Expert(s) referred to in this document shall consist of one or more persons appointed by and serving at the pleasure of the IESG. The procedure described for Expert Review assignments in this document is consistent with the IANA Expert Review policy described in . While finite, the universe of MAC code points from which Expert-judged assignments will be made is felt to be large enough that the requirements given in this document and the Experts' good judgment are sufficient guidance. The idea is for the Expert to provide a light sanity check for small assignments of EUI identifiers, with increased scrutiny by the Expert for medium-sized assignments of EUI identifiers and assignments of protocol identifiers and other IANA OUI-based parameters. However, it can make sense to assign very large portions of the MAC identifier code point space. (Note that existing assignments include one for 1/2 of the entire multicast IANA EUI-48 code point space and one for 1/16 of that multicast code point space.) In those cases, and in cases of the assignment of "reserved" values, IESG Ratification of an Expert Review approval recommendation is required as described below. The procedure is as follows: The applicant always completes the appropriate template from Appendix A below and sends it to IANA <iana@iana.org>. IANA always sends the template to an appointed Expert. If the Expert recuses themselves or is non-responsive, IANA may choose an alternative appointed Expert or, if none is available, will contact the IESG. In all cases, if IANA receives a disapproval from an Expert selected to review an application template, the application will be denied. The Expert should provide a reason for refusal which IANA will communicate back to the applicant. If the assignment is based on Expert Review: If IANA receives approval and code points are available, IANA will make the requested assignment. If the assignment is based on IESG Ratification: The procedure starts with the first steps above for Expert Review. If the Expert disapproves the application, they simply inform IANA who in turn informs the applicant that their request is denied; however, if the Expert believes the application should be approved, or is uncertain and believes that the circumstances warrant the attention of the IESG, the Expert will inform IANA about their advice, and IANA will forward the application, together with the reasons provided by the Expert for approval or uncertainty, to the IESG. The IESG must decide whether the assignment will be granted. This can be accomplished by a management item in an IESG telechat as is done for other types of requests. If the IESG decides not to ratify a favorable opinion by the Expert or decides against an application where the Expert is uncertain, the application is denied; otherwise, it is granted. The IESG will communicate its decision to the Expert and to IANA. In case of refusal, the IESG should provide a reason which IANA will communicate to the applicant.

IANA Web Page Changes For clarity and parallelism with the IANA "IEEE 802 Numbers" web page, the IANA "Ethernet Numbers" web page is re-named the "IANA OUI Ethernet Numbers" web page. As this document replaces , references to in IANA registries on both the IANA IEEE 802 Numbers web page and the IANA IETF OUI Ethernet Numbers web pages will be replaced by references to [this document]. Other IANA web page references to are not changed.

MAC Address AFNs and RRTYPEs IANA has assigned Address Family Numbers (AFNs) for MAC addresses as follows:

AFN	Decimal	Hex	Reference
48-bit MAC	16389	0x4005
64-bit MAC	16390	0x4006
24-bit OUI	16391	0x4007
Lower 24 bits of a 48-bit MAC address:
MAC/24	16392	0x4008
Lower 40 bits of a 64-bit MAC address:
MAC/40	16393	0x4009

IANA has assigned DNS RRTYPEs for MAC addresses as follows:

		RRTYPE Code
Data	Mnemonic	Decimal	Hex	Reference
48-bit MAC	EUI48	108	0x006C
64-bit MAC	EUI64	109	0x006D

Informational IANA Web Page Material IANA maintains an informational listing on its web site concerning Ethertypes, OUIs, and multicast addresses assigned under OUIs other than the IANA OUI. The title of this informational registry is "IEEE 802 Numbers". IANA will update that informational registry when changes are provided by or approved by the Expert(s).

Ethertype Assignment Process Applying to the IEEE Registration Authority for an Ethertype needed by an IETF protocol is a fairly simple clerical process but requires IESG approval as stated in Appendix B. To minimize confusion, this process will normally be done by the primary expert for the informational IANA 802 Numbers Ethertype registry (see Section 5.2). After IESG approval of the protocol requiring an Ethertype, the IESG should refer the matter to IANA. In any case, IANA will ask the IANA IEEE 802 Numbers Ethertype registry to execute the IEEE Ethertype assignment request process.

OUI Exhaustion When the available space for either multicast or unicast EUI-48 identifiers under OUI 00-00-5E has been 90% or more exhausted, IANA should request an additional OUI from the IEEE Registration Authority for further IANA assignment. The appointed Expert(s) should monitor for this condition and notify IANA.

IANA OUI MAC Address Table No changes are made by this document to the "IANA Unicast 48-bit MAC Addresses" and "IANA Multicast 48-bit MAC Addresses" tables except for the updates to references as specified in Section 5.2.

IANA LLDP TLV Subtypes IANA is requested to move the "IANA Link Layer Discovery Protocol (LLDP) TLV Subtypes" Registry from the IANA IEEE 802 Numbers web page to the IANA OUI Ethernet Numbers web page, since code points within it are assigned by IANA, and to add [this document] as an additional reference for that registry. In addition, IANA is requested to update three entries in that Registry as follows:

Value	Description	Reference
0	Reserved	[this document]
42	Example for use in documentation	[this document]
255	Reserved	[this document]

The entries for 1 (MUD), 2-41 (unassigned), and 43-254 (unassigned) are unchanged.

CBOR Tag Assignments IANA is requested to assign two CBOR Tags as shown below. [The values of 48 and 49 are requested for TBD1 and TBD2 respectively.]

Tag	Data Item	Semantics	Reference
TBD1	byte string	IEEE MAC Address	[this document]
TBD2	byte string	IEEE OUI/CID	[this document]

Security Considerations This document is concerned with assignment of IEEE 802 parameters allocated to IANA, particularly those under the IANA OUI, and closely related matters. It is not directly concerned with security except as follows: Confusion and conflict can be caused by the use of MAC addresses or other OUI-derived protocol parameters as examples in documentation. Examples that are "only" to be used in documentation can end up being coded and released or cause conflicts due to later real use and the possible acquisition of intellectual property rights in such addresses or parameters. The reservation herein of MAC addresses and parameters for documentation purposes will minimize such confusion and conflict. See for security considerations on storing MAC addresses in the DNS.

Normative References IEEE 802 IEEE 802 Informative References IANA IANA IEEE IEEE 802 IEEE 802 IEEE 802 IEEE 802 IEEE 802 IEEE 802 IEEE RA IEEE SA IEEE IEEE InfiniBand Trade Association IANA

Templates This appendix provides the specific templates for IANA assignments of parameters. Explanatory words in parentheses in the templates below may be deleted in a completed template as submitted to IANA.

EUI-48/EUI-64 Identifier or Identifier Block Template Applicant Name: Applicant Email: Applicant Telephone: (starting with country code) Use Name: (brief name of Parameter use such as "Foo Protocol" ) Document: (ID or RFC specifying use to which the identifier or block of identifiers will be put.) Specify whether this is an application for EUI-48 or EUI-64 identifiers: Size of Block requested: (must be a power-of-two-sized block, can be a block of size one (2**0)) Specify multicast, unicast, or both:

IANA OUI/CID-Based Protocol Number Template Applicant Name: Applicant Email: Applicant Telephone: (starting with country code) Use Name: (brief name of use of code point such as "Foo Protocol") Document: (ID or RFC specifying use to which the protocol identifier will be put.) Note: (any additional note)

Other IANA OUI/CID-Based Parameter Template Applicant Name: Applicant Email: Applicant Telephone: (starting with country code) Protocol where the OUI/CID-Based Parameter for which a value is being requested appears: (such as: Cipher Suite selection in IEEE 802.11) Use Name: (brief name of use of code point to be assigned, such as "Foo Cipher Suite" [RFC3092]) Document: (ID or RFC specifying use to which the other IANA OUI-based parameter value will be put.) Note: (any additional note)

Ethertypes This appendix provides a copy of the IESG Statement issued in October 2012 on obtaining new IETF Ethertypes in Section B.1. Note that there is an informational list on the IANA web site of some important Ethertypes specified for IETF protocols or by IEEE 802 available, currently at . The IEEE Registration Authority page of Ethertypes, http://standards.ieee.org/regauth/ethertype/eth.txt, may also be useful. See Section 3 above.

IESG Statement on Ethertypes From: IESG Date: 25 October 2012 The IEEE Registration Authority (IEEE RA) assigns Ethertypes with oversight from the IEEE Registration Authority Committee (IEEE RAC). (See http://standards.ieee.org/develop/regauth/ethertype/.) Some IETF protocol specifications make use of Ethertypes. All Ethertype requests are subject to review by a consultant to the IEEE RA followed by IEEE RAC confirmation. Since Ethertypes are a fairly scarce resource, the IEEE RAC has let us know that they will not assign a new Ethertype to a new IETF protocol specification until the IESG has approved the protocol specification for publication as an RFC. In exceptional cases, the IEEE RA is willing to consider "early allocation" of an Ethertype for an IETF protocol that is still under development as long as the request comes from and has been vetted by the IESG. To let the IEEE RAC know that the IESG has approved the request for an Ethernet assignment for an IETF protocol, all future requests for assignment of Ethertypes for IETF protocols will be made by the IESG. Note that playpen Ethertypes have been assigned in IEEE 802 [1] for use during protocol development and experimentation. [1] IEEE Std 802a-2003 (Amendment to IEEE Std 802-2001). IEEE standard for Local and Metropolitan Area Networks: Overview and Architecture -- Amendment 1: Ethertypes for Prototype and Vendor-Specific Protocol Development.

Acknowledgements The comments and suggestions of the following people persons and organizations are gratefully acknowledged: Comments and suggestions leading to this Document: Carsten Bormann Comments and suggestions leading to RFC 7042 (which is obsoleted by this document): David Black, Adrian Farrel, Bob Grow, Joel Jaeggli, Pearl Liang, Glenn Parsons, Pete Resnick, and Dan Romascanu.